package JDBC;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCDemo7 {
    public static void main(String[] args) {
        /**
         *
         * SELECT COUNT(*)
         * FROM student s
         * JOIN class c ON
         *
         *
         *
         */


        try(
                Connection connection = DBUtil.getConnection()
                ){
            Statement statement = connection.createStatement();
            String sql="SELECT COUNT(*) count " +
                    "FROM student s " +
                    "JOIN class c ON s.class_id =c.id " +
                    "WHERE c.name='1年级1班'";
                     ResultSet rs=statement.executeQuery(sql);
                             if(rs.next()){
                                 int count=rs.getInt("count");
                                 System.out.println("共"+count+"人");
                             }
        }catch (SQLException e){
            e.printStackTrace();
        }




















    }


}


